At that point, it should verify your connection information. If
you've misspelled your account name or password, you will have to
fix them before you can proceed.

To use the phone optimally with FastMail, there are some Advanced settings that should be adjusted. Before that can happen, it is important for the iPhone/iPod to connect to the server once to download the list of folders from the FastMail server.

This is easy to do, simply press the home button, then choose Mail and highlight your new mail account. If you are currently viewing your Inbox, you can press the "Back" button with your account name at the top of the page. This will list all the folders on the FastMail server. Items such as Drafts, Sent Items, Trash.

You are now ready to configure the Advanced settings. The benefit will be that all messages you send or delete from your iPhone will be visible from the FastMail webmail interface, or other email programs you have configured.

Choose Drafts Mailbox. You will then see the folder list "On
the Server". Find your Drafts folder on the server and select
it. Click the Advanced button at the top left when done.

Next choose Sent Mailbox. Find your Sent Items folder on the
server and select it. Click the Advanced button at the top left when
done.

Finally, choose the Deleted Mailbox. Find the Trash folder
on the server and select it.

You are complete. Simply press the Home button to finish the
configuration.

Once your configuration is complete, your iPhone will work perfectly with FastMail.

Some other items to consider:

You do not necessary have to set the IMAP Prefix on the iPhone
to be INBOX. For our business customers, leaving the prefix blank
allows your iPhone to see any shared email folders that exist in
your business.

If you use mostly utilize a public WiFi to access your email using
your iPhone or iPod Touch, these can sometimes cause connection
issues. That is due to the WiFi provider being very restrictive
regarding the ports that are made available. Not to worry, you can
change your email configuration to utilize our Proxy services. The
proxy allows you to use IMAP over any port necessary (usually port
80 is available). You can learn more about our proxy servers
here.